#555BBF
Closest named color: Iris (#6258C4). oklch(51.9% 0.154 277), rgb(85, 91, 191).
Aa
White text reads best on this color (5.77:1).
About this color
#555BBF is a medium-dark, vivid blue. In OKLCH its lightness is 52%, its chroma 0.154 and its hue 277°. Its hue sits on the cool side of the wheel. The nearest named color is Iris (#6258C4), ΔE 0.021 away. White text reads best on it, at 5.77:1.
| Hue family | Blues |
| Lightness | medium-dark (52%) |
| Chroma | vivid (0.154) |
| Temperature | cool |
| Nearest name | Iris (#6258C4) |
| Black text | 3.63:1 |
| White text | 5.77:1 |
Values
| HEX | #555BBF |
| RGB | rgb(85, 91, 191) |
| HSL | hsl(237, 45%, 54%) |
| OKLCH | oklch(51.9% 0.154 277) |
Contrast
WCAG 2 contrast ratios are the conformance target: AA needs 4.5:1 for body text and 3:1 for large text, AAA needs 7:1. APCA Lc values are supplementary guidance from the WCAG 3 drafts.
| Pair | WCAG 2 | Result | APCA | APCA guidance |
|---|---|---|---|---|
| White text on #555BBF | 5.77:1 | AA | Lc -83.9 | Fine for body text |
| Black text on #555BBF | 3.63:1 | AA large text | Lc 25.4 | Dividers and decoration only |
| #555BBF text on white | 5.77:1 | AA | Lc 78.6 | Fine for body text |
| #555BBF text on black | 3.63:1 | AA large text | Lc -23.2 | Dividers and decoration only |
Tints and shades
A 50–950 scale built in OKLCH: the hue is held, lightness follows a Tailwind v4-like curve, and every step is kept inside the sRGB gamut. This color sits at step 700.
-
Step 50
50
#F3F5FC
oklch(97.1% 0.01 273.4)
-
Step 100
100
#E6E9F9
oklch(93.6% 0.022 277.5)
-
Step 200
200
#D2D7F5
oklch(88.5% 0.042 278)
-
Step 300
300
#B4BDF1
oklch(80.9% 0.074 277)
-
Step 400
400
#8E99EA
oklch(70.7% 0.119 277)
-
Step 500
500
#747DE4
oklch(63.1% 0.153 277.3)
-
Step 600
600
#5E64D2
oklch(55.6% 0.166 277.2)
-
Step 700
700 (this color)
#555BBF
oklch(51.9% 0.154 277)
-
Step 800
800
#3F4493
oklch(42.7% 0.128 276.8)
-
Step 900
900
#353A75
oklch(37.6% 0.1 276.8)
-
Step 950
950
#1F2245
oklch(26.9% 0.064 277.4)
#555BBF with color blindness
Simulated with the Machado et al. (2009) model. ΔE is how far the color moves: below about 0.02 you would not notice a change.
| Vision | Seen as | Shift (ΔE) |
|---|---|---|
| Protanopia (no red cones) | #236AC3 | 0.057 |
| Deuteranopia (no green cones) | #0F61BD | 0.061 |
| Tritanopia (no blue cones) | #1E7284 | 0.136 |
| Achromatopsia (no color) | #666666 | 0.154 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #555BBF
#555BBF
oklch(51.9% 0.154 277)
- #7A6800
#7A6800
oklch(51.9% 0.107 97.2)
Analogous
Neighbouring hues, 30° either side.
Split complementary
The two hues beside the complement (150° and 210°).
Triadic
Three hues spaced 120° apart.
Palettes with this color
Curated palettes that contain a color within ΔE 0.04 (OKLab) of #555BBF, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Iris #6258C4 ΔE 0.021
- Slate Blue #6A5ACD ΔE 0.038
- Dark Periwinkle #665FD1 ΔE 0.039
- Light Indigo #6D5ACF ΔE 0.044
- Warm Blue #4B57DB ΔE 0.047
- French Blue #436BAD ΔE 0.057
- Bluey Purple #6241C7 ΔE 0.061
- Royal Blue #4169E1 ΔE 0.062
Use #555BBF in your product
Turn it into light and dark UI roles checked for contrast, then export to Tailwind v4, shadcn/ui, CSS or design tokens.